Self-centering chuck



1950 c. H. VIDAL 2,535,106

' SELF-CENTERING cr-wcx Filed June 30, 1947 4 Sheets-Sheet 2 Dec. 1950 c. H. VlDAL 2,535,106

- SELF-CENTERING CHUCK- Filed June 50, 1947 4 Sheets-Sheet 3 Dec. 26 1950 c. H. VlDAL 2,535,106

SELF- CENTERING CHUCK Filed June 30, 1947 4 Sheets-Sheet 4 Patented Dec. 26, 1950 UNITED STATES ATENT OFFICE SELF-CENTERXNG CHUCK Vidal, deceased Application June 30, 1947, Serial No. 758,165 In Great Britain October 10, 1946 (C1. WISE-58) 10 Claims.

This invention relates to improvements in selfcentering chucks of the kind in which the jaws are so mounted that axial pressure applied to the inner end of the jaws causes the jaws to move radially inwards and in which operating means are provided for effecting said axial pressure.

According to this invention, a self-centering chuck of the kind referred to is characterised in that the means of applying axial pressure to the jaws comprises an axially-guided plunger engaging the jaws, a lever mounted to pivot about an axis which is fixed in relation to the chuck body against movement away from the plunger and having a part engaging said plunger so that pivotal movement of the lever imparts axial movement to the plunger and means for applying said pivotal movement.

In one form of construction a lever is pivoted to the chuck body by a ball and socket joint.

The lever may extend on either side of the pivotal mounting and has one end engaging an end face of the plunger, while the other end is engaged by an operating member movable in a direction transverse to the direction of movement of the plunger.

The end face of the lever which contacts with the plunger is so shaped that when the lever rocks about its pivotal mounting its end face has a camming action on the plunger. For example, in one arrangement the abutting faces of the plunger and lever may have flat portions and the fiat portion on the end of the lever may be flanked by rounded portions.

The other end of said lever which is engaged by the operating member may be provided with a spherical or rounded portion which engages a flat end face of the operating member which is movable transversely to the rotation axis.

The operating member may comprise a threaded plug engaging a threaded bore in the chuck body extending transversely to the axis of the chuck. In an alternative arrangement one end of said lever is arranged pivctally to engage said plunger and the other to engage an operating member constrained to move transversely to said rotation axis. For example, both ends of said lever are rounded and engage rounded sockets formed in said plunger and operating member. A transversely-extending shaft is rotatably mounted in the chuck body and is arranged to engage a threaded bore in said operating member which member is provided with a flat face which slidably engages a flat face on the chuck body.

In either of the arrangements referred to above the jaws may be provided with outer conical faces which are arranged to engage an inner conical face of a sleeve connected to the chuck body so that when axial pressure is applied to the end of the jaws, relative movement takes place between the engaging conical faces causing the aforesaid radial movement of the jaws. The aforesaid sleeve may be provided with internal thread for engaging a threaded part of the chuck body whereby relative axial movement between the conical faces may be effected by rotation of the sleeve relatively to the chuck body in addition to the operation of the aforesaid plunger.

The following is a more detailed description of two embodiments of the invention, reference being made to the accompanying drawings in which- Figure 1 is a longitudinal section through one form of chuck on the line ll of Figure 2;

Figure 2 is a cross-section on the line 2-2 of Figure 1;

Figure 3 is a similar view to Figure l of an alternative form of chuck showing the jaws in an open position;

Figure 4 is a section on the line 4-4 of Figure 3; and

Figure 5 is a part longitudinal section and side elevation of the chuck.

The chuck body comprises a cylindrical part is having at one end a conical bore or a threaded stem l l for engagem nt with that part of the machine tool with which the chuck is to be employed and the other end of which is provided with a cylindrical bore !2 terminating at its inner end in a spherical seat 53 encircling a smaller cylindrical bore :4. This end of the chuck body is externally threaded at 5. The chuck body is also provided with one or more internally threaded passages H3 extending transversely to the axis of rotation of the chuck and intercepting the smaller cylindrical bore beyond the spherical seat. A threaded plug ll may be arranged to engage each of said threaded passages, the outer end of the plug being provided with a socket l8 for engagement by a key and the inner end of the ping being provided with a fiat face l9. Disposed within the larger cylindrical bore is a plunger 20 having a circumferential groove 2i and flat end faces 22, 23. A lever member 215 for operating the plunger comprises a part spherical portion 25 which rests on the aforesaid spherical seating l3 and has provided on a face 26 disposed opposite the end of the plunger a projection 21 having a convexly curved periphery 28 and a flat end face 29 which abuts the fiat face 23 of the plunger.

On the opposite side of the spherical portion is a cylindrical stem 24 terminating in an enlarged spherical portion 30, one side of which abuts the fiat end H) of the aforesaid threaded plug ll. Thus, by screwing the plug into and out of the threaded passage the lever member may be tilted on the spherical seat I3 causing a camming action between the flat face 29 of the aforesaid projection and the face of the plunger 29. The other end face 22 of the plunger engages the end faces of the chuck jaws 3! which are provided in the conventional manner with conical outer faces engaging a conical internal face 32 on a sleeve 33 in threaded engagement with the threaded part of the chuck body.

The jaws are urged apart by springs 34 or by resilient means such as is described in the specification of British patent application No. 33,989/46.

In the arrangement shown in Figures 3 to 5, the lever member 24 is provided with rounded ends 35 and 36 which engage spherical ended sockets 3! and 38 formed respectively in the plunger 20 and an operating member 39. The operating member is provided with a flat face 40 which slidably engages a flat face of a partition wall 4! between the cylindrical bore 32 and conical socket l I. The operating member is also provided with a threaded cross bore 42 which is engaged by a threaded plug 63 having enlarged head 45 located in recesses 45 in the chuck body which prevent enclosure movement of the plug. The enlarged heads are provided with suitablyshaped sockets 46 for engagement by an operating key.

The other parts of the chuck are similar to those of the construction shown in Figures 1 and 2.

I claim:

1. A self-centering chuck comprising a hollow chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with the longitudinal axis thereon inclined to the rotation axis, one end of which lever pivotally abuts said plunger and another part of which lever is provided with a part spherical surface and which chuck is provided with a part spherical surface for engaging a spherical surface of said lever, and means for imparting a pivotal movement to said lever.

2, A self-centering chuck comprising a hollow chuck body having an internal camming face, a number of .iaws engaging said face. a p unger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with its longitudinal axis inclined to said rotation axis, one end of which lever pivotally abuts said plunger, which lever is provided with a part spherical surface intermediate of its end and which chuck body is provided with a part spherical socket for engaging the part spherical surface of the lever, an operating member mounted in the chuck body so as to be movable in a direction transverse to said axis of rotation and engaging that end of the lever remote from the plunger.

3. A self-centering chuck comprising a hollow chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with its longitudinal axis inclined to said rotation axis and the end of which lever pivotally abuts said plunger, which abutting parts are provided with fiat surfaces so that pivotal movement efiects camming action on said plunger and moves it axially and which lever is provided 5 with a part spherical surface intermediate of its ends and which chuck body is provided with a. part spherical socket for engaging the art spherical surface of the lever, an operating member mounted in the chuck body so as to be movable in a direction transverse to said axis of rotation and engaging that end of the lever remote from the plunger.

4. A self-centering chuck comprising a hollow chuck bod having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with its longitudinal axis inclined to said rotation axis and an end of which lever pivotally abuts said plunger, and is so shaped that pivotal movement imparts axial movement to the plunger, which lever is provided with a part spherical surface intermediate of its ends and which chuck bod is provided with a part spherical socket engaging the part spherical surface of said lever arm, an operating member mounted in said chuck body and movable transversely to the rotation axis and having a flat end face engaging a rounded side face of said lever.

-uck comprising a hollow g internal camming face, a number aivs engaging said face, a plunger send jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with its longitudinal axis inclined to s d rotat on axis and an end of which lever zivotally abuts said plunger, and is so shaped that pivotal movement imparts axial movement to the plun er, which lever is provided wit a part spherical surface intermediate of its ends and which chuck body is provided with a part spherica socket engaging the part spherical surface of said lever arm, an operating member having theaded shank which engages the threaded bore in said chuck body and provided with flat end face for engaging the rounded side face of said lever.

6. A self-centering chuck compris ng a hollow chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said and movable along the axis of rotation of the chrck, a lever mounted in said chuck body with ts longitud nal axis inclined to said rotation axis and having one end pivotilly abutting said plunl, r, an operating member mounted in said chuck body so as to be constrained. to move transversely to said rotational ax s, which st ng member is adapted pivotally to engage the otn end of said lever.

7. A sehcent ing chuck comprising a hollow chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis "er, an operating member consaid chuck body transversely as and having a socket adapted the other end of said lever. 8. A self-ce--ter. .g chuck comprising a hollow chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body with its longitudinal axis inclined to said rotation axis and having one end pivotally abutting said plunger, an externally threaded operating member rotatably mounted in said chuck body and engaging a nut portion constrained against rotational movement and having a socket adapted pivotally to engage the other end of said lever.

9. A self-centering chuck comprising an externally threaded hollow chuck body, an internally threaded sleeve engaging said chuck body and having an internal conical camming face, a number of jaws having external part conical faces engaging said camming face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body to pivot about an axis transverse to and fixed against movement along the rotation axis, the longitudinal axis of which lever is inclined to said rotation axis and the end of which lever abuts against said plunger and means for imparting ivotal movement to said lever.

10. A self-centering chuck comprising a hol- 20 Number low chuck body having an internal camming face, a number of jaws engaging said face, a plunger engaging said jaws and movable along the axis of rotation of the chuck, a lever mounted in said chuck body so that a part thereof pivots on a part of the chuck body about an axis transverse to and fixed against movement along the rotation axis, the longitudinal axis of which lever is inclined to said rotation axis and the end of which lever abuts and rocks against said plunger and means for imparting pivotal movement to said lever.

CHARLES HENRY VIDAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 725,346 Krug Apr. 14, 1903 921,721 1,680,631

Palaith Aug. 14, 1928 Kopsch May 12, 1936 Mellis May 18, 1909 

